Index: trunk/src/plugins/rt_topo/crbs.c
===================================================================
--- trunk/src/plugins/rt_topo/crbs.c	(revision 1391)
+++ trunk/src/plugins/rt_topo/crbs.c	(revision 1392)
@@ -250,6 +250,7 @@
 
 	for(a = gdl_first(&crbs->grbs.all_arcs); a != NULL; a = gdl_next(&crbs->grbs.all_arcs, a)) {
 		if (!a->in_use) continue;
+		if ((a->r == 0) || (a->da == 0)) continue;
 		rtrnd_arc_new(ly_drw, NULL, NULL, a->parent_pt->x, a->parent_pt->y, a->r, a->sa, a->da, 0.2, 0);
 		if (ly_out != NULL) {
 			o = rtrnd_arc_new(ly_out, NULL, NULL, a->parent_pt->x, a->parent_pt->y, a->r, a->sa, a->da, rt_topo_cfg.wire_thick, 0);